Via Tim I discovered the Observer’s architect critic has joined the chorus demanding the horror of Preston Bus Station be saved. The main argument appears to be that it ” it embodies the spirit of its 1960s age”, you can argue if that is a good or bad thing visually but in the world of civil engineering, particularly those parts related to large concrete car park type structures, that is reason enough to flatten it. Indeed the man himself admits the reason before attempting to dismiss it;

“The bus station is not alone. It is part of a company of buildings from the 1960s and 70s that fall victim to a vicious compound of circumstances. They are tough, not obviously charming and carry a label no PR expert would have chosen, of “brutalism”. Some have serious technical problems, albeit often exaggerated. Some have serious technical problems, albeit often exaggerated“

I will now demonstrate why those serious technical problems have not been exaggerated. We begin in the 1960s when reinforced concrete was a new idea and building huge civic structures in the brutalist style was all the rage. After the architect had produced his swooping lines and grand gestures for the new Preston depot he handed it over to the designers to do the actual hard part of making it work and not fall down, and here is were things went a bit wrong. To be blunt the concrete specifications of the time allowed fairly weak, porous concrete and didn’t require much cover to the reinforcing steel, for those interested in water/cement ratios and porosity of concrete I commend you to this handy government guidance. To add to the fun the design codes of the time were also a bit ‘optimistic’ on concrete strength in shear so most designs weren’t really strong enough and didn’t have the safety margins the designers assumed.

So fast forward a few decades to the 1990s and these chickens begin to roost, car parks start rotting far faster than planned and a few demolition contractors get nasty surprises when the buildings fall apart faster than expected. The big change is probably Pipers Row car park, the top floors of which quite dramatically collapse overnight;

Pipers Row Car Park, pride of Wolverhampton. It got it's own HSE report you know, where do you think I nicked the photo from?

After the HSE investigation a whole generation of material engineers relax knowing their careers will be safe for life, looking after corroding 1960s/70s car parks will be a job for life for anyone who cares to do so. While the collapses generally get avoided these days that doesn’t mean the buildings are OK, it just means they get demolished earlier than expected leaving the owners to try and explain the problem to confused punters looking to park. A good one was Heathrow Terminal 3 car park;

You may be forgiven for thinking this was just part of the ongoing 'permanent rebuild' strategy for Heathrow Airport. However this is the old T3 car park, the one that was conveniently opposite the terminal till it was condemned by a mate of mine due to massive corrosion. So this car park was demolished and a new one built further away. If you've ever been at T3 and wondered why the car park is so far away and why the pick-up/drop off area is so huge, that's why.

This is still a live problem, a quick google throws up a car park in Nottingham that got the old ’emergency closure’ treatment a couple of years back and only last month a Southend car park collapsed during demolition, the top five stories letting go as they had corroded far worse than previously thought. It should now be obvious why Preston Bus Depot has to go, it’s not going to last long in any event so better to take it out while it’s safe before it decides to do the job itself.

I will leave the final word for today to another article in the Guardian, quoting a former Secretary of State for culture when the first listing of the depot was rejected;

“It therefore appears to the secretary of state that the main attractive feature of the design was the result of a miscalculation which led to a poor quality of construction.”

You know you said “Yes” to the wrong overtime opportunity when you spend the early hours of Saturday night/Sunday morning huddling in the exhaust fumes of a diesel generator because, though the fumes are unpleasant and it’s noisy, it is at least warm and out of the wind.

This was going to be a point and laugh post about an article on El Reg, the thrust of which was ‘A little knowledge is a dangerous thing’ as the author has got his Heathrow Terminals mixed up and has confused two jobs that occurred almost a decade apart, thus making him look like an idiot. OK making him look like an idiot to tunnel engineers but getting away with it for the other 99.9% of the readership. But still the Heathrow collapse had bugger all to do with Terminal 5, primarily because it occurred just outside Terminal 3 in 1994 well over 10 years before Terminal 5 had even started construction. But then he is a Project Manager and so I suppose I shouldn’t expect him to do ‘facts’

I was then pondering a discussion on TfL’s approach to risk based on the interesting quotes in the article from the TfL head of risk management as he was responsible for risk on the Heathrow job. Alas it doesn’t say which Heathrow job, if it was T5 he did a fairly good job on the engineering side (the baggage system which failed was all M&E and they’ve always been useless bastar….) but if he was on the original Heathrow Express in 1994 that makes it very interesting, particularly given what the Heathrow Express collapse did to London Underground’s approach to risk (I really must write the Jubilee Line Extension post one day). Without knowing which I’d be guessing, and if I’m going to do that I might as well guess about something interesting and just make up some exciting stuff.

So as I have to do something, and it should involve risk, I’ll merely note that the biggest punishment on Balfour Beatty wasn’t the fine (£1.3 million, even in the 1990s, wasn’t that much to a big civil engineering contractor) or the damaged reputation with clients it was insurance. Post the collapse (and post the JLE insurance fiasco) Balfour’s couldn’t get insurance for a tunnel job for love nor money for almost a decade. While they did finish out existing contracts they didn’t start a new job in tunnelling till the middle of this decade. You may say that’s a harsh price to pay, but if you were to take a look at the roof and walls of Heathrow Terminal 4 station you may change your mind.

An occasional series looking at why the Germans are the last people I would ask to build a tunnel. Today’s lesson was prompted by the on-going archiving at work which dug up this fun project from the vaults;

Today’s triumph of German precision and efficiency is the 1994 Munich U-Bahn collapse. Essentially while using the world’s least reliable tunnelling system they managed to bugger up construction of the U2 line tunnel so badly the road above collapsed under the weight of a passing bus. Hilarity failed to ensue when several of the passengers failed to escape in time.

This is bad enough but it’s not like they weren’t warned; there had been a very similar (if non-fatal) collapse while building the U1 line. German tunnelling collapses is the gift that keeps on giving, so this series should run and run.

Today was an unusual one as it involved grappling with the question ‘Does that tunnel need closing?’

Technically I’ve done this many times before, every tunnel inspection ends with someone ticking the box marked ‘Tunnel is safe’ on their big compliance sheet, however as you may have guessed from that description of the it’s normally as much for form’s sake as anything else. Certainly it’s very rare to actually find anything of note, all the old Victorian tunnels that were built badly have long since fallen down (leaving only the good ones) and the newer stuff just doesn’t go wrong as there is so little to go wrong.

This time however we received a nice report saying a tunnel had moved a worrying large amount, hasn’t actually stopped moving and is right on the edge of the trigger level marked “COLLAPSE”. The question therefore was should the client close the tunnel or should they throw a load of realtime monitoring at it to try and work out exactly what is going on. We did in the end recommend the latter, if the client had in fact closed this tunnel I suspect it would have made the national news. In fact given the site and it’s history it may even have made it further afield, though who can fathom the world of the news editor’s priority list?

As always with these bits of news I feel I probably can’t go into detail as the company involved would not be impressed, which is something of a shame as it’s the kind of story I just know would make a nice splash in the tabloids and thus get me my few minutes of blogging fame. Ah well.